US Marine General Frank McKenzie arrived in the United Arab Emirates on Sunday for talks on efforts to bolster the Gulf state’s defences aftera series of missile attacks launched by Houthi fighters in Yemen. In recent weeks, the Iran-aligned Houthis have waged an unprecedented string of largely failed missile strikes on UAE targets that have triggered Emirati and US air defences and seen American troops briefly taking shelter. The attacks have thrown a spotlight on so-far unsuccessful UN-led efforts to broker an end to the war in Yemen, which since 2015 has pitted the Houthis against a Saudi A…